为什么我的数组发送到函数后为空 [英] Why my Array is empty after sent into function

问题描述

我想将几个parameters发送到function中，其中一个是array. 在调用function之前，数组包含多个项目，通过函数内部的调试器查看时，array为empty\null:

I want to send several parameters into function and one of them is array. Before call the function the array is with several items, when looking via the debugger inside the function the array is empty\null:

$arr = New-Object System.Collections.ArrayList 
$arr.Add("test1")
GetProcessOutput -exeFile "c:\file.exe" -args $arr

function GetProcessOutput($exeFile, $args)
{
    # here my $args is empty -> children could not be evaluated
}

推荐答案

$args是

$args is a automatic variable, meaning that you are prevented from using the args name for a user-defined variable.

使用任何其他名称，它将起作用:

Use any other name and it'll work:

function GetProcessOutput([string]$exeFile,[array]$arguments)
{
    # $arguments will work just fine
}

---

从 about_Variables帮助文件:

---

From the about_Variables help file:

 There are several different types of variables in Windows
 PowerShell.

-- User-created variables: User-created variables are created and 
   maintained by the user. By default, the variables that you create at
   the Windows PowerShell command line exist only while the Windows 
   PowerShell window is open, and they are lost when you close the window.
   To save a variable, add it to your Windows PowerShell profile. You can 
   also create variables in scripts with global, script, or local scope.    

-- Automatic variables: Automatic variables store the state of 
   Windows PowerShell. These variables are created by Windows PowerShell, 
   and Windows PowerShell changes their values as required to maintain 
   their accuracy. Users cannot change the value of these variables.
   For example, the $PSHome variable stores the path to the Windows 
   PowerShell installation directory. 

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